Well, here is a list of most of the ones you could see on match night.

Boarding
Striking the clenched fist of one hand into the open palm of the opposite hand in front of the chest.

Butt Ending
A cross motion of the forearms, one passing under the other.

Charging
Rotating clenched fists around one another in front of the chest.

Checking from behind
A forward motion of both arms, with the palms of the hands open and facing away from the body, fully extended from the chest at shoulder level.

Crosschecking
A forward motion with both fists clenched extending from the chest.

Delayed calling of penalty or other violation

Extend arm fully above the head (hand without whistle). Blow whistle when penalised team has puck possession. It is acceptable to point at the player once then extend the arm above the head.

Elbowing
Tapping either elbow with the other hand.

Goal
Referee to point into the net.

Hand pass
Use open palm of hand in a pushing motion.

High sticking
Holding both fists clenched, one immediately above the other at the height of the shoulders

Holding
Clasping either wrist with the other hand, in front of the chest

Hooking
A tugging motion with both arms, as if pulling something from in front into the stomach.

Icing the puck
The back referee or linesman signals a possible icing by fully extending his arm without the whistle over his head. The front referee or linesman indicates the icing is completed by extending his arm above his head. The back referee or linesman then blows his whistle and skates to the face off spot. When he is standing on the spot he crosses his arms to indicate the icing.

Interference
Crossed arms with closed fists stationary in front of the chest

Kneeing
Slapping either knee with the palm of the hand while keeping both skates on the ice

Match
Pat flat of hand on the top of the head.

Penalty Shot

Arms crossed above the head, give the signal upon stoppage in play.

Roughing
Fist clenched and arm extended out to the side of the body.

Slashing
A chopping motion with the edge of one hand across the opposite forearm.

Spearing
A jabbing motion with both hands thrust out directly in front of the body.

Tripping
With both skates on the ice striking right leg with the right hand below the knee.

Washout
Referee makes this signal to indicate that an apparent goal will not count, as either it was illegally obtained or the puck did not actually cross the goal line.